import Foundation

public enum MinimizedWindowFallbackPolicy {
    public static let syntheticWindowIDMarker: UInt32 = 0x8000_0000

    public static func shouldCreateAXOnlyFallback(hasCGWindowID: Bool, isMinimized: Bool) -> Bool {
        !hasCGWindowID && isMinimized
    }

    public static func isSyntheticWindow(_ window: AlignerWindow) -> Bool {
        window.identifierSource == .syntheticAX
    }

    public static func syntheticWindowID(
        processIdentifier: Int32,
        windowIndex: Int,
        title: String,
        subroleDescription: String,
        occupiedWindowIDs: Set<UInt32> = []
    ) -> UInt32 {
        let key = "\(processIdentifier)|\(windowIndex)|\(title)|\(subroleDescription)"
        var candidate = syntheticWindowIDMarker | (fnv1a32(key) & ~syntheticWindowIDMarker)

        while candidate == 0 || occupiedWindowIDs.contains(candidate) {
            candidate = syntheticWindowIDMarker | ((candidate &+ 1) & ~syntheticWindowIDMarker)
        }

        return candidate
    }

    private static func fnv1a32(_ value: String) -> UInt32 {
        var hash: UInt32 = 2_166_136_261
        for byte in value.utf8 {
            hash ^= UInt32(byte)
            hash = hash &* 16_777_619
        }
        return hash
    }
}